Why does the Volkswagen Magotan engine shake slightly when just started?
2 Answers
There are several reasons for the Magotan's cold start shaking: 1. Low ignition energy: When the car starts cold, the temperature inside the engine is insufficient, and the temperature of fuel and lubricating oil is not enough. After long-term use, the spark plug's ignition gap increases, leading to reduced ignition energy, affecting power performance and causing the car to shake. 2. Carbon deposits on valves and intake passages: If carbon deposits occur on the valves and intake passages inside the engine, the carbon deposits can absorb an appropriate amount of fuel, causing the ECU to make incorrect judgments and fail to achieve the required power performance, resulting in shaking. 3. Inappropriate mixture ratio: Incorrect adjustment of the air-fuel mixture ratio and non-functioning oxygen sensor. In this case, the ECU makes judgment errors, leading to inaccuracies in controlling the air-fuel mixture and ignition timing through the actuators, reducing the car's power output and causing shaking.
My Magotan has been running for over five years, and I've also experienced occasional shaking during cold starts. The main reason is that the engine oil hasn't fully lubricated yet, especially noticeable in low winter temperatures. Additionally, aging spark plugs or faulty ignition coils can cause misfires in individual cylinders, making the car body shake severely. Carbon buildup in the fuel injectors can also lead to uneven fuel delivery, causing an imbalance in the air-fuel mixture during cold starts and resulting in shaking. I recommend first checking if the engine oil needs changing, as a clogged fuel filter can also cause unstable fuel supply. If the shaking stops after the engine idles smoothly, there's generally no need to worry—just use fuel additives regularly to clean carbon deposits.
